/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.transaction.support;

import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.aop.scope.ScopedObject;
import org.springframework.core.InfrastructureProxy;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;

/**
 * Utility methods for triggering specific {@link TransactionSynchronization}
 * callback methods on all currently registered synchronizations.
 *
 * @author Juergen Hoeller
 * @see TransactionSynchronization
 * @see TransactionSynchronizationManager#getSynchronizations()
 * @since 2.0
 */
public abstract class TransactionSynchronizationUtils {

    private static final Log logger = LogFactory.getLog(TransactionSynchronizationUtils.class);

    private static final boolean aopAvailable = ClassUtils.isPresent(
            "org.springframework.aop.scope.ScopedObject", TransactionSynchronizationUtils.class.getClassLoader());


    /**
     * Check whether the given resource transaction managers refers to the given
     * (underlying) resource factory.
     *
     * @see ResourceTransactionManager#getResourceFactory()
     * @see org.springframework.core.InfrastructureProxy#getWrappedObject()
     */
    public static boolean sameResourceFactory(ResourceTransactionManager tm, Object resourceFactory) {
        return unwrapResourceIfNecessary(tm.getResourceFactory()).equals(unwrapResourceIfNecessary(resourceFactory));
    }

    /**
     * Unwrap the given resource handle if necessary; otherwise return
     * the given handle as-is.
     *
     * @see org.springframework.core.InfrastructureProxy#getWrappedObject()
     */
    static Object unwrapResourceIfNecessary(Object resource) {
        Assert.notNull(resource, "Resource must not be null");
        Object resourceRef = resource;
        // unwrap infrastructure proxy
        if (resourceRef instanceof InfrastructureProxy) {
            resourceRef = ((InfrastructureProxy) resourceRef).getWrappedObject();
        }
        if (aopAvailable) {
            // now unwrap scoped proxy
            resourceRef = ScopedProxyUnwrapper.unwrapIfNecessary(resourceRef);
        }
        return resourceRef;
    }


    /**
     * Trigger {@code flush} callbacks on all currently registered synchronizations.
     *
     * @throws RuntimeException if thrown by a {@code flush} callback
     * @see TransactionSynchronization#flush()
     */
    public static void triggerFlush() {
        for (TransactionSynchronization synchronization : TransactionSynchronizationManager.getSynchronizations()) {
            synchronization.flush();
        }
    }

    /**
     * Trigger {@code beforeCommit} callbacks on all currently registered synchronizations.
     *
     * @param readOnly whether the transaction is defined as read-only transaction
     * @throws RuntimeException if thrown by a {@code beforeCommit} callback
     * @see TransactionSynchronization#beforeCommit(boolean)
     */
    public static void triggerBeforeCommit(boolean readOnly) {
        for (TransactionSynchronization synchronization : TransactionSynchronizationManager.getSynchronizations()) {
            synchronization.beforeCommit(readOnly);
        }
    }

    /**
     * Trigger {@code beforeCompletion} callbacks on all currently registered synchronizations.
     *
     * @see TransactionSynchronization#beforeCompletion()
     */
    public static void triggerBeforeCompletion() {
        for (TransactionSynchronization synchronization : TransactionSynchronizationManager.getSynchronizations()) {
            try {
                synchronization.beforeCompletion();
            } catch (Throwable tsex) {
                logger.error("TransactionSynchronization.beforeCompletion threw exception", tsex);
            }
        }
    }

    /**
     * Trigger {@code afterCommit} callbacks on all currently registered synchronizations.
     *
     * @throws RuntimeException if thrown by a {@code afterCommit} callback
     * @see TransactionSynchronizationManager#getSynchronizations()
     * @see TransactionSynchronization#afterCommit()
     */
    public static void triggerAfterCommit() {
        invokeAfterCommit(TransactionSynchronizationManager.getSynchronizations());
    }

    /**
     * Actually invoke the {@code afterCommit} methods of the
     * given Spring TransactionSynchronization objects.
     *
     * @param synchronizations a List of TransactionSynchronization objects
     * @see TransactionSynchronization#afterCommit()
     */
    public static void invokeAfterCommit(@Nullable List<TransactionSynchronization> synchronizations) {
        if (synchronizations != null) {
            for (TransactionSynchronization synchronization : synchronizations) {
                synchronization.afterCommit();
            }
        }
    }

    /**
     * Trigger {@code afterCompletion} callbacks on all currently registered synchronizations.
     *
     * @param completionStatus the completion status according to the
     *                         constants in the TransactionSynchronization interface
     * @see TransactionSynchronizationManager#getSynchronizations()
     * @see TransactionSynchronization#afterCompletion(int)
     * @see TransactionSynchronization#STATUS_COMMITTED
     * @see TransactionSynchronization#STATUS_ROLLED_BACK
     * @see TransactionSynchronization#STATUS_UNKNOWN
     */
    public static void triggerAfterCompletion(int completionStatus) {
        List<TransactionSynchronization> synchronizations = TransactionSynchronizationManager.getSynchronizations();
        invokeAfterCompletion(synchronizations, completionStatus);
    }

    /**
     * Actually invoke the {@code afterCompletion} methods of the
     * given Spring TransactionSynchronization objects.
     *
     * @param synchronizations a List of TransactionSynchronization objects
     * @param completionStatus the completion status according to the
     *                         constants in the TransactionSynchronization interface
     * @see TransactionSynchronization#afterCompletion(int)
     * @see TransactionSynchronization#STATUS_COMMITTED
     * @see TransactionSynchronization#STATUS_ROLLED_BACK
     * @see TransactionSynchronization#STATUS_UNKNOWN
     */
    public static void invokeAfterCompletion(@Nullable List<TransactionSynchronization> synchronizations,
                                             int completionStatus) {

        if (synchronizations != null) {
            for (TransactionSynchronization synchronization : synchronizations) {
                try {
                    synchronization.afterCompletion(completionStatus);
                } catch (Throwable tsex) {
                    logger.error("TransactionSynchronization.afterCompletion threw exception", tsex);
                }
            }
        }
    }


    /**
     * Inner class to avoid hard-coded dependency on AOP module.
     */
    private static class ScopedProxyUnwrapper {

        public static Object unwrapIfNecessary(Object resource) {
            if (resource instanceof ScopedObject) {
                return ((ScopedObject) resource).getTargetObject();
            } else {
                return resource;
            }
        }
    }

}
